Add 'Testing Rails Applications' to the site index

...so it shows up at the right place in the sites dropdown

Author: tjgrathwell

lib/site_index.rb

@@ -4,10 +4,25 @@ class SiteIndex < Erector::Widget
 
   def categorized_sites
     {
-      'setup' => ['installfest'],
-      'rails' => ['intro-to-rails', 'job-board', 'message-board'],
-      'frontend' => ['frontend', 'javascript-snake-game', 'javascript-to-do-list', 'javascript-to-do-list-with-react'],
-      'ruby' => ['learn-to-code', 'ruby']
+      'setup' => [
+        'installfest'
+      ],
+      'rails' => [
+        'intro-to-rails',
+        'job-board',
+        'message-board',
+        'testing-rails-applications'
+      ],
+      'frontend' => [
+        'frontend',
+        'javascript-snake-game',
+        'javascript-to-do-list',
+        'javascript-to-do-list-with-react'
+      ],
+      'ruby' => [
+        'learn-to-code',
+        'ruby'
+      ]
     }
   end